How to figure this out yourself:
1. Launch two Blocklands
2. On one, make a server
3. On the other, join that server.
4. On the Blockland running the server, make a minigame
5. On the other Blockland, join that minigame
6. On the server, open the console, type trace(1);
7. Kick the other client from the minigame through the UI, as you normally would
8. Type trace(0); in the console
9. You can now see any function that have been called between trace calls. In here will be any clientside functions called when you click the gui button, and since you're also running the server on that same game, the serverCmd called when the server recieves the request
Since I don't know the appropriate serverCmd name of the top of my head, this is the exact steps I would follow to find it. Might as well teach you so you can be self-sufficient